Problem: $ { \left[\begin{array}{rrr}{4} & {0} & {-2} \\ {3} & {0} & {1}\end{array}\right]+\left[\begin{array}{rrr}{1} & {1} & {3} \\ {-2} & {-1} & {-1}\end{array}\right] = {?} } $
Answer: To find the sum of two matrices, add the corresponding items between each matrix. ${\left[\begin{array}{rrr}{4}+{1} & {0}+{1} & {-2}+{3} \\ {3}+{-2} & {0}+{-1} & {1}+{-1}\end{array}\right]}$ Now, simplify: ${\left[\begin{array}{rrr}{5} & {1} & {1} \\ {1} & {-1} & {0}\end{array}\right]}$